1. Field of Invention
The present invention relates to flexible lustered products used, for example, as automobile radiator grilles. More particularly, the present invention relates to flexible lustered products having a base material formed from flexible resin and a surface with metallic luster.
2. Brief Description of the Related Art
As shown in FIG. 9, a typical flexible lustered product 51 includes a base material 52, which is formed from a material such as polyurethane, a base coat layer 53, which is a coating applied to the base material 52, a metal film layer 54, which is applied to the base coat layer 53, and a top coat layer 55, which is applied to the metal film layer 54. The base coat layer 53 has a mirror smooth surface to enable satisfactory application of the film layer 54. The top coat layer 55 protects the film layer 54.
The metal film layer 54 is formed from a continuous film that results in several problems. For example, the 25 application of an external force to the lustered product 51 may result in distortion or deformation of the product 51. Among the elements constituting the lustered product 51, the base material 52, the base coat layer 53, and the top coat layer 55 restore their original form after the application 30 of the external force. However, since the film layer 54 is made of a single sheet of metal film, it cannot tolerate as much deformation. As shown in FIG. 10, when the lustered product 51 is deformed by a large external force (arrow 57), the film layer 54 cannot follow the deformation of the base material 52 and the layers 53, 55. Thus, a relatively large stress acts on the film layer 54. This may form cracks 56 in the film layer 54. The cracks 56 appear as white streaks and thus deteriorate the appearance of the lustered product 51.
Japanese Unexamined Patent Publication No. 9-70920 describes a metal film layer that solves the above problems. The metal film layer is made of an anticorrosive metal and has a thickness that is at least 150 xc3x85 and at most 180 xc3x85. The metal film layer also has grain boundaries.
When an external force acts on the flexible lustered product of Publication No. 9-70920, the base material, which is made of a flexible resin material, the base coat layer, and the top coat layer deform in accordance with the external force. The fine metal particles forming the metal film layer are visually perceived as a metal film having a uniform surface. However, due to the grain boundaries of the metal film layer, the application of an external force just moves adjacent crystal grains (metal grains) apart from each other and widens the distance between the crystal grains. This suppresses the formation of cracks and prevents deterioration of the appearance of the product. In addition, the anticorrosive property of the film layer prevents corrosion.
However, the metal film layer of the above publication 30 is still problematic in that the adhesion of the metal film layer to the base coat layer and the top coat layer is insufficient. This is because the base coat layer and the top coat layer are made of a resin material. Therefore, when the lustered product is used under harsh conditions or over a long period of time, the base coat layer and the top coat layer may peel off the metal film layer.
When a flexible lustered product is employed, for example, on the exterior of an automobile, paint is often applied to the top coat layer. In such case, the solvent included in the paint may cause swelling of the top coat layer. If the level of swelling becomes high, the adhesiveness between the metal film layer and the base coat layer becomes further insufficient. This may also result in the top coat layer peeling off the metal film layer.
Accordingly, it is an objective of the present invention to provide a flexible lustered product that prevents cracks from forming in its metal film layer, prevents deterioration of the quality of the outer appearance, and prevents peeling between its layers.
To achieve the above objective, the present invention provides a flexible lustered product including a base material made of resin. A base coat layer is formed on at least a portion of a surface of the base material by applying a coating. The base coat layer has a glass transition point that is at least xe2x88x9230xc2x0 C. and at most 0xc2x0 C. The base coat layer includes a silane coupling agent having a mercapto group. A metal film layer is applied to at least a portion of a surface of the base coat layer. The metal film layer is anticorrosive and has a thickness that is at least 150 xc3x85 and at most 800 xc3x85. The metal film layer is formed by a plurality of metal particles disposed in contact with one another so as to define a grain boundary between adjacent metal particles. A top coat layer is formed on at least a portion of a surface of the metal film layer by applying a coating.
A further aspect of the present invention provides a flexible lustered product including a base material made of resin. A base coat layer is formed on at least a portion of a surface of the base material by applying a coating. A metal film layer is applied to at least a portion of a surface of the base coat layer. The metal film layer is anticorrosive and has a thickness that is at least 150 xc3x85 and at most 800 xc3x85. The metal film layer is formed by a plurality of metal particles disposed in contact with one another to define a grain boundary between adjacent metal particles. A top coat layer is formed on at least a portion of a surface of the metal film layer by applying a coating. The top coat layer has a swelling rate of at least 100% and at most 150%. Furthermore, the top coat layer includes a silane coupling agent having a mercapto group.
Another aspect of the present invention provides a flexible lustered product including a base material made of resin. A base coat layer is formed on at least a portion of a surface of the base material by applying a coating. The base coat layer has a glass transition point that is at least xe2x88x9230xc2x0 C. and at most 0xc2x0 C. The base coat layer includes a silane coupling agent having a mercapto group. A metal film layer is applied to at least a portion of a surface of the base coat layer. The metal film layer is anticorrosive and has a thickness that is at least 150 xc3x85 and at most 800 xc3x85. The metal film layer is formed by a plurality of metal particles disposed in contact with one another so as to define a grain boundary between adjacent metal particles. A top coat layer is formed on at least a portion of a surface of the metal film layer by applying a coating. The top coat layer has a swelling rate of at least 100% and at most 150%. The top coat layer also includes a silane coupling agent having a mercapto group.
Other aspects and advantages of the present invention will become apparent from the following description, taken in conjunction with the accompanying drawings, illustrating by way of example the principles of the invention.